Low mutual coupling T-shaped two-port slot antenna

A two-port slot antenna featuring low mutual coupling is proposed. It is achieved using only the radiator itself without the need of any additional structure. The mechanism is elaborated using transmission line theory. The series short stub, which is part of the radiating element, can effectively de-couple the two ports. Following the idea, a compact two-port slot antenna on PCB is designed working around 2.94 GHz. The area of the antenna in terms of wavelength in air is 0.196×0.294 λ_o². Measurement results shows that the mutual coupling in terms of S₂₁ is less than -10 dB within -10-dB bandwidth. The gain and efficiency are 1.670 dBi and 47.71 % respectively if one port is excited while the other one is terminated with matched load.